This invention relates to an apparatus for evening the fiber sliver or fiber lap in a card, a roller card unit or similar machine which has a licker-in (fiber opening roller), a feed roller arranged immediately upstream of the licker-in as viewed in the direction of material feed, a feed table which cooperates with the feed roller and which is arranged to be relatively movable with respect to the feed roller for executing shifts relative to the feed roller as a function of the thickness (quantity) of the fiber material passing through the gap defined by the feed table and the feed roller. Further, with the feed table there is associated a measuring member which emits signals representing the relative displacement of the feed table and which is connected with the drive motor for the feed roller by means of a control device.
In a known apparatus disclosed, for example, in French published Application No. 2,322,942, underneath the stationarily held feed roller there is provided a stationary support, on which a plurality of sensor levers (feed table) are movably arranged. One end of each sensor lever is spring-loaded and is situated in the immediate vicinity of the licker-in. At the other end of each sensor lever there is arranged a measuring device (sensor pedal) which senses the shifts of the sensor lever as a function of the thickness of the material passing therethrough. It is a disadvantage of this arrangement that as the feed roller engages the fiber material and takes over the feed thereof, the working forces derived from the licker-in (tearing forces) exert an effect on the sensor levers and thus tend to distort the results of the measurements. It is another disadvantage of such a prior art arrangement that the measuring location in the clamping zone between the feed roller and the sensor levers extends over a relatively long path as viewed in the direction of article advance in which the feed roller is situated opposite the sensor levers and thus the location of the measurement is not accurately determinable.